Bassanio has already managed to borrow a large sum of money from his friend, Antonio, so that he can go to Belmont and try his hand at marrying Portia, a woman who has been left with a large sum of money following her father's death. In Act II scene 2, Launcelot, a servant of Shylock, asks for and is given a new job as Bassanio's servant, and at the end of this scene, Gratiano asks if he can accompany Bassanio. Bassanio initially does not welcome this request, as Gratiano is not a serious enough figure to take with him, and he is concerned that Gratiano's jocularity might not help him as he seeks Portia's hand. He does allow Gratiano to accompany him, but note what advice he gives him:

Bassanio tells him to use "modesty" to keep his character in check, referring to Gratiano's happy-go-lucky nature as his "skipping spirit," and using the metaphor of comparing modesty to "cold drops" in order to convey to Gratiano how he has to cool down and become more serious if he is to go to Belmont with him. If not, Bassiano fears that his intentions will be misunderstood and "misconstrued," and his hopes of marrying Portia will be lost. In response, Gratiano promises faithfully that he will be serious, but then insists he be allowed to party as he wants to do so tonight. Bassanio agrees, as he says that they have friends that need the kind of merriment and humour that Gratiano can bring.